The present invention relates to an EGR mixer arrangement for mixing the gas into the intake air of a turbocharged internal combustion engine, comprising an inlet port with connection for a branch pipe, which with an insertion section opens out into the inlet port.
The recirculation of exhaust gases, so-called Exhaust Gas Recirculation (EGR), is a commonly known method of influencing the combustion in internal combustion engines and means that a proportion of the total exhaust gas flow from the engine is returned in a secondary flow to the intake side of the engine where it is mixed with the intake air for delivery into the engine cylinders. When combustion occurs with a reduced oxygen content, due to EGR admixture, the combustion temperature is reduced. This makes it possible to reduce the quantity of nitrogen oxides (NOx) in the exhaust gas emissions discharged into the surrounding environment.
The quantity of EGR gas that can be transferred from the exhaust side to the intake side of a turbocharged internal combustion engine varies, among other things, as a function of the pressure prevailing on the intake side and on the exhaust side, and on the design configuration of the EGR mixer arrangement for mixing the gas into the intake air. This arrangement should therefore be designed for a minimum pressure fall both of the intake air and of the EGR gas. The arrangement should furthermore be capable of distributing the pulsed supply of EGR gas as uniformly as possible to all engine cylinder chambers. Unfortunately, in internal combustion engines for heavy trucks there is generally a lack of space in the engine compartment. It is therefore a problem to provide an EGR mixer arrangement which fulfills the efficiency requirements whilst at the same time being compact.
It is desirable therefore to provide a compact and efficient exhaust gas recirculation mixer arrangement.
An arrangement according to an aspect of the present invention comprises an inlet port with connection for a branch pipe, which with an insertion section opens out into the inlet port, and according to the invention is characterized in that the insertion section forms a diffuser vane with a surface which is positively double-bent in the direction of flow of the intake air and which extends in a curved shape in the flow direction of the inlet port. This design of the mixer arrangement achieves an efficient mixing of the EGR gas into the intake air over a short section of the port.
Advantageous exemplary embodiments of the invention are set forth in the following description.